I also fully agree with the OP (and many others in this thread) that UE4 really needs a stability release rather than super-fancy cutting-edge features every single month. It’s great to have awesome graphics and stuff, but what good are all these shiny features if basic tech does not work?
Also I don’t understand the bug fixing policy at Epic. There are some bugs that have been reported months ago, Epic replies with something like “Thanks for the bug report, bug UE-xyz has been recorded, we’ll get back to you.” And nothing happens. Why isn’t Epic just addressing those bugs? Here are some examples:
- Custom mouse cursors have been buggy for months, and HW cursors are not even supported yet
- Reimporting FBX models does not work without issues
- Gameplay Developer Tools (GDT) do not work on non-US keyboards (see end/bottom of that link)
This list goes on and on, just have a look at the answer hub and this forum for more examples. Obviously not every bug is a game breaker for anyone, but some of them are more than just annoying and need to be fixed, no matter what.
And that brings me back to my original question: What is the bug-fixing policy at Epic?
- Why would I need procedural foliage systems if I cannot even reimport FBX models?
- Why would I need advanced EQS for my AI if I cannot even use basic AI debugging features?
- Why would I need fancy rendering capabilities if I cannot even render a custom (hardware) cursor?
I really do like UE4, and I want to use it. We have committed our to UE4, and it would be a disaster for us to switch to another engine at this point. However, having to spend half of our dev time to find, identify, report and work around bugs is really bad for our mood. It doesn’t make our devs want to work with UE4, which is quite sad 
TL;DR – We fully support the idea of something like a “maintanance” release in 4.9. The most sophisticated and shiny new features are of no use if the basic features don’t work reliably or at all.